Infection 4 Flashcards by Noah Havers

What are healthcare infections?

Infections arising as a concequence of providing healthcare that are:

Not present nor incubation at admission (onset 48hrs after admission)
Found in patient, visitors and healthcare workers

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Give some common examples of infections due to medical practice

Surgical site infection

Central line associated bloodstream infection

Ventilator associated pnuemonia

Catheter associated UTI

Clostridium difficile Infection

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Give some examples of common viruses that cause HAI

Hep B, C

HIV

Norovirus

Influenza

Chickenpox

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Give some examples of common bacteria that cause HAI

Staph aureus

C. difficile

E. coli

Klebsiella pnuemoniae

Pseudomonas aeruginosa

Mycobacterium tuberculosis

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Give some common examples of fungi causing HAI

Candida albicans

Aspergillus spp.

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Give an examples of a common parasite that can cause HAI

Malaria

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What patient factors predispose to HAI?

Extremes of age (young/old)

Obesity/malnourishment

Cancer

Immunosuppression

Smoker

Surgical patient

Emergency admission

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What are the 4 Ps of infection control?

Patient

Pathogen

Practice

Place

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What are the patient factors contributing to infection control?

General and specific patient risk factors

Interactions with:

Other patients
Healthcare workers
Visitors

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what are the pathogen factors relevant to infection control?

Virulence factors

Ecological interactions:

Other microbes
Antibiotics/disinfectants

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What are the healthcare environment factors relevant to infection control?

Activities of HCWs directly related to treatment

Policies and their implementation

Organisational structures

Regional and national political initiatives

Leadership from ward to government

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What are the general interventions aimed at reducing patient’s risk of acquiring a healthcare infection

Optimise condition (Smoking, nutrition, diabetes)

Antimicrobial prophylaxis

Prevention of commensal spread:

Skin preparation
Hand hygiene

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What are the more specific/targetted interventions aimed at reducing patient risk of HAI?

MRSA screening

Mupirocin nasla ointment (Prevent aerosol spread of infection)

Disinfectant body wash

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Give some examples of how we might halt patient to patient spread of infection?

Isolation of infected/susceptible patients:

Separate rooms
Positive pressure in rooms
Air filtration

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How do we prevent spread of HAI from healthcare workers?

Disease free and vaccinated staff

Good practice:

Sterile non-touch techniques

Hand hygiene

Personal protection equipment (Face masks, aprons, gloves)

Antimicrobial prescribing to HCPs

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What are the environmental interventions to prevent patient infection from water and food?

Appropriate kitchen and ward food facilities

Food food hygiene (sterile food)

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What are the environmental interventions that can prevent infection of patients from surfaces?

Cleanliness of built environment:

Toilets
Wash hand basins
Furniture

Cleaning:

Disinfectant
Steam cleaning
H2O2 vapour

Medical devices:

Single use equipment
Sterilisation
Decontamination

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How can ward layout affect HAI?

Overcrowding of bed put patients in closer proximity, aiding spread of infection

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How is diagnoses of necrotising fasciitis made?

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Suspicision of deep seated infection in an acutely unwell patient supported by relevant labs (WBC, CRP etc)

Surgical exploration to confirm

What are the common features of someone with a necrotising fasciitis infection?

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Extreme pain in infected area

High temp, pulse

Hypotensive

Raised WBCs

How might we manage a patient with necrotising fasciitis?

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Supportive care (Fluid resus)

Analgesia

Antibiotics

Surgical/ITU referral

Describe the surgical management of necroising fascitis?

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Initial fasciotomy

Assesment of deep tissue (may require debridement)

May require amputation

Skin grafting if patient survives

What factors influence our choice of antibiotic when treating an infection?

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Severity

Site

Likely pathogens

Route of administration

Adverse affects:

- Allergy/reaction*
- Interactions with other drugs*
- Renal/hepatic impairment*

What are the likely pathogens of necrotising fasciitis infection?

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Group A Beta-haemolytic streptococci (E.g. Strep. pyogenes

What is the gram stain appearance of Streptococci?

G+

Describe the different types of streptococcal haemolysis Give examples of species of each type

**Alpha:** Oxidise iron turning dark green in culture S. Pneumoniae **Beta:** Completely rupture blood cells S. Pyogenes **Gamma:** Non-haemolytic

Give an example of a non-haemolytic cocci

Enterococcus Faecalis

Describe the pathogenesis of streptococci **Hint:** Give toxin/structure and its effect

**M proteins:** Component of cell wall Antiphagocytic **Exotoxins:** Pyrogenic exotoxins (Superantigens) - Cause rash Streptolysin O and S (Cell lysis) **Streptokinase:** Lysis of clots **Streptodornase:** DNAase promoting spread of infection **C5a peptidase:** Inactivation of complement

What antibiotics are used to treat Streptococcal infection?

B-lactams and glycopeptides Some macrolides and tetracyclines

How might we directly target toxin mediate disease as a result of infection?

**Anti-toxin therapy:** High dose human Ig **Interfere with toxin synthesis:** Antibiotics that target protein synthesis (E.g. Clindamycin, Rifampicin)

Give the specifics of necrotising fasciitis antibiotic treatment

**Empiric:** Tazocin + Clindamycin **If group A Beta-haemolytic Streptococci (GAS) identified:** Tazocin + Benzylpenicillin **Consider adding high dose Ig**

Give some other diseases caused by Group A Beta-haemolytic streptococci (GAS)

Acute pharyngitis/tonsilitis (With rash = scarlet fever) Impetigo Puerperal sepsis

Give 2 post-streptococcal infection sequelae How does each come about?

**Acute rheumatic fever (2-3 wks post):** Cross reaction between heart/joint tissues and strep antigens (esp M protein) **Acute glomerulonephritis (1 wk post):** Antigen-antibody complexes on basement membrane of glomerulus post infection

Give examples of conditions caused by Alpha-haemolytic streptococci (Viridans)

Infective endocarditis Pneumonia, Meningitis (S. Pneumoniae)

Give possible infections caused by Gamma-haemolytic 'streptococci'

Enterococcus Faecalis - Abdo sepsis, UTI

What are the clinical signs of scarlet fever?

Erythematous blanching rash Circumoral pallor Strawberry tongue Tonsilitis/Pharyngitis (sore throat, fever)

Give some exampes of common staphylococcal infections

Impetigo Furuncles (boils - E.g. facial 'spots') Surgical wound infections

What is impetigo? Give two common causative organisms

Skin infection **Symptoms:** Red rash Develops into sores that leak pus/fluid Can cause fluid flilled blisters (Mostly in under 2s) **Organisms:** Staph. aureus Strep. pyogenes

What is the appearance of staphylococci after gram staining?

G+

What is the coagulase test and what organisms does it differentiate?

**Differentiation:** Tests staphylococci spp for presence of coagulase enzyme (Converts fibrinogen to fibrin) Staph aureus is coagulase positive Most others are coagulase negative **Testing:** Done on a slide or in a tube Involves inoculation of plasma with staphylococcus organisms

What are the common antibitoics used against staphylococcus spp.? ## Footnote **Hint: Remember resistance**

**Flucloxacillin:** Resistant to staphylococcus B-lactamase **Some cephalosporins** **Some B-lactamase/B-lactamase inhibitor combos:** Co-amoxiclav, Tazocin **Glycopeptides:** Vancomycin Often in MRSA infection

Describe the pathogensis of C. diff

**Enterotoxin (C. diff toxin A):** Increases Cl- channel permeability in the mucosal cells of gut lumen (intestines) Secretory diarrhoea results **Cytotoxin (C. diff toxin B):** Causes actin depolymerisation **Overall:** Infection leads to Dairrhoea and Intestinal inflammation

How is the severity of C diff infection assessed?

**Severe infection (Any of below):** - Sepsis or temp = \>38.3C - Albumin \< 25g/l, WBC \> 15 x 109/L, elevated creatinine (\>50% above baseline) - Signs of severe colitis or pseudomembranous colitis

What antibiotics are reccomended for treatment of C. diff?

Non-severe = Metronidazole Severe = Vancomycin + Metronidazole (if vancomycin underwhelming in effect)

What are the concequences of norovirus infection?

**Viral gastroenteritis:** Vomitting Diarrhoea Dehydration

How should a patient with norovirus be treated on the ward?

Isolated PPE used by healthcare workers Sterile/non-touch technique for all procedures where possible Disinfection of area (Chlorine based)

Infection 4 Flashcards

(46 cards)